00:00I used to think that gold was one of the rarest elements in the universe, but turns out that's
00:04not entirely true. In fact, gold is everywhere. It's just that most of it is really hard to find
00:10because it's inside rocks like this one called peridotite. Peridotite is mostly made up of two
00:16minerals, olivine and pyroxine, and these two minerals have a lot of iron, magnesium, and
00:22calcium in them. This is why when you look at the Earth's mantle on Google Earth, it's all green.
00:28Green is the color of the Earth's mantle, but sometimes this rock has a little bit of something
00:33else, a little bit of gold. Now, since gold is so dense, if you're looking for it in this rock,
00:40it's basically like finding a needle in a haystack, so no one really bothers looking for it, but once
00:46in a while, gold will appear on the surface of the Earth's mantle. And when that happens, we call it an
00:52ultramafic rock. These rocks are still mostly green, but they also have veins of black minerals
00:58like chromite and magnetite, and in between those black minerals is some gold. The good news is that
01:05these rocks are really easy to find because they stick out. The bad news is that there's not very
01:11much gold in them, so mining these rocks isn't very profitable. NASA, though, doesn't mine their gold.
01:17They steal it from other planets. And let me tell you, that's a lot easier than mining it here.
01:24Gold is actually really abundant on asteroids. In fact, there's a whole group of asteroids that
01:29are mostly made up of gold. For example, there's 16 Psyche. It's named after the Greek goddess of the
01:36soul. And its official name is 16 Psyche, provisional designation 2013 TV 135. Its diameter is about 270
01:47miles or 435 kilometers across. And scientists estimate that it's worth around 10 quadrillion dollars.
01:54That's 10 with a Q. And that's just Psyche. There are plenty more asteroids like that. But the real
02:01question is, how do you get it off the asteroid? Well, it turns out that gold is soft. In fact,
02:07it's the second softest element on the periodic table. Only cesium is softer. That means that if
02:14you hit gold with enough force, it will dent. And if you can dent it, you can vaporize it.
02:19You see, when something gets really, really cold, it becomes really, really hard. And when something
02:25gets really, really hot, it becomes really, really soft. That's what makes Psyche such a
02:31good target for mining. It's big, and it's made of gold. But Psyche isn't close enough to the earth
02:37for NASA to use lasers to vaporize the gold. So instead, they'd have to send a mining ship out
02:42to it. And then on this mining ship, they would have a drill that could bore a hole into the surface
02:47of Psyche. Once the drill was in deep enough, they could start vaporizing the gold with a laser.
02:54Then all they'd need to do is scoop it up and bring it home. Easy profit. Except, uh-oh,
03:00looks like a bunch of meteorites just destroyed Psyche. So maybe try a different asteroid.
03:06Asteroid 3361 resolved by the impact is probably still intact. And if NASA goes there and uses the
03:13same strategy, they can make a decent profit. After all, 3361 resolved is worth around $10 billion.
03:22That's 10 with a B. But the thing is, NASA can't mine asteroids with lasers unless they first map the
03:29surface of the asteroid. And to map the surface of the asteroid, they need gold. Gold is the
03:35perfect material for making a spacecraft heat shield because it reflects 95% of the sunlight
03:42that hits it. That leaves only 5% of the energy from the sun actually hitting the spacecraft.
03:48So with a gold heat shield, NASA can protect their spacecraft from getting burned up during
03:53atmospheric re-entry. And without gold, they wouldn't be able to land spacecraft on Mercury.
03:59And if they can't land spacecraft on Mercury, they can't map the surface of Mercury. And if they can't
04:05map the surface of Mercury, they can't mine Mercury. And if they can't mine Mercury, they can't build a
04:11base on Mercury. And if they can't build a base on Mercury, they won't be able to launch their mining
04:17ships to asteroids. And if they can't mine asteroids, they won't have any money to buy gold.
04:24And if they don't have any gold, they can't make heat shields and they can't go to Mercury.
04:28And if they can't go to Mercury, they can't map Mercury. Okay, got it. So where does NASA get
04:35their gold? Will they mine it? Of course, NASA mines gold right here on the Earth. They've been
04:42doing it for years. I mean, if NASA can't even mine gold here on Earth, how are they going to go
04:47out to Mercury and mine it in space? But where do they mine it? Well, one place they go is South
04:53Africa. That's because South Africa has the world's deepest gold mine. It's called the Emponeng Mine.
05:00It's under the city of Carltonville. The entrances are right next to each other. One leads to the
05:06Emponeng Mine, and the other leads to the Val River. You can see the entrance to the Val River
05:12on Google Earth. It's this black hole here. If you zoom in, you can see the entrance to the
05:18Emponeng Gold Mine right beside it. This mine is 3.8 kilometers deep. And to put that in perspective,
05:25that's deeper than the Mariana Trench. The Mariana Trench is 6.8 miles deep.
05:31The Emponeng Gold Mine is 2.4 miles deep. That's almost as deep as the mine as the deepest part of
05:37the ocean. But that's nothing compared to the Kolar Gold Mine. The Kolar Gold Mine is located
05:42in India. It's right outside the city of Kolar. And the entrances are hidden in the forest. You can
05:49see the forest on Google Earth. You can also see where the entrances are. But can you see the
05:54entrances? Well, you can if you zoom in. These two dark spots are the entrances to the Kolar Gold Mine.
06:00These entrances lead down to 2.7 miles deep, which is 350 meters deep. This is deeper than the Emponeng
06:08Gold Mine, but it's still nowhere near as deep as the Earth. The Earth is 12,142 kilometers deep.
06:15That means that all of these mines are pretty shallow. In fact, they're so shallow that if you
06:20wanted to drill a hole all the way through the Earth, you wouldn't even break the crust. The crust is
06:2640 kilometers thick. And if you drilled through the crust, you'd end up in the mantle. But you don't
06:31want to go in the mantle because the mantle is too hot. So where does NASA get their gold? Well,
06:37they mine it right here on Earth, just like I said. But the thing is, they don't mine it very much.
06:44All they need is a few kilograms every year, which is not very much at all. So where do they get it?
06:49Well, it turns out that NASA gets most of their gold from military contractors. You see, the U.S.
06:56military is always working on new weapons and technologies, and sometimes they create materials
07:02that NASA needs. For example, the U.S. military once created a material called gold titanium,
07:09which is 90% efficient at reflecting radio waves. NASA realized that this material would be great for
07:15protecting spacecraft from radio wave radiation. So they started buying it from the military.
07:21Another reason why NASA doesn't mine their own gold is because it's too expensive.
07:26For example, a pound of gold costs $400,000. And if you're going to ship that gold to another planet,
07:33it'll cost you millions of dollars. So instead, NASA just buys the gold from companies like Credit Suisse
07:40and HSBC.
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